A semiconductor light-emitting element such as a light-emitting diode (LED) is used as a point source for a light source for camera shooting of a mobile phone. To effectively use light emitted from a point source such as an LED, a collimator lens is used, which emits a maximum amount of light as parallel light (refer to patent literature 1 for example).
The collimator lens disclosed in patent literature 1 has a recess formed therein as a space for accommodating an LED. The recess is enclosed with a first face, which is a curved face formed opposite to the optical axis of the LED; and a refractive inner wall, which is a curved face. The first face forms a light-incoming face for letting light into the lens. The refractive inner wall is provided to let light that deviates laterally outward from the optical axis out of light from the LED, into the lens. The outer face formed largely expanding from the recess to the outside has a curved total reflection face formed therein.
This configuration, however, requires two major components: a recess and an outer face largely expanding outside the recess, which prevents the width from becoming smaller, resulting in a large-size collimator lens.